The miniature portrait of the first woman barrister at the Old Bailey – who has a Blue Plaque above her former Silchester Road home – is expected to be sold for around £1,000.

It will be up for auction at Duke’s Auctioneers in Dorchester, Dorset, in March.

“This small portrait is an amazing snippet of history in which you can see a Woman of survival, dedicated to equal rights,” Mr Medhurst said.

“It is a wonderful thing to be able to look at the same lady who would have looked at my Great Grandfather over 100 years ago on board a lifeboat in the middle of the Atlantic Ocean.”

Ms Bowerman had a Blue Plaque posthumously awarded to her St Leonards home in November, 2005.

She was a member of Emmeline Pankhurst’s Women’s Social and Political Union, she also witnessed the Russian Revolution in 1917 and was the first head of the UN Commission on the Status of Women in 1947.

She was on the Titanic with her mother Edith, setting off from Warrior’s Square to Southampton on April 10, 1912.